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Date: Mon, 29 Jan 2024 14:55:47 +0000
From: Matthew Wilcox <willy@infradead.org>
To: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: Manas Ghandat <ghandatmanas@gmail.com>,
	Linux-kernel-mentees@lists.linuxfoundation.org,
	jfs-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org,
	syzbot+411debe54d318eaed386@syzkaller.appspotmail.com,
	Sasha Levin <sashal@kernel.org>
Subject: Re: [PATCH] jfs: fix shift-out-of-bounds in dbJoin
Message-ID: <Zbe8c_CPNP8IdphB@casper.infradead.org>
References: <20231011143937.31996-1-ghandatmanas@gmail.com>
 <Zba9zRWq6rZhWn-p@casper.infradead.org>
 <a25c75af-c961-4ca6-9810-dbcfe64753d5@oracle.com>
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On Mon, Jan 29, 2024 at 08:39:18AM -0600, Dave Kleikamp wrote:
> On 1/28/24 2:49PM, Matthew Wilcox wrote:
> > On Wed, Oct 11, 2023 at 08:09:37PM +0530, Manas Ghandat wrote:
> > > Currently while joining the leaf in a buddy system there is shift out
> > > of bound error in calculation of BUDSIZE. Added the required check
> > > to the BUDSIZE and fixed the documentation as well.
> > 
> > This patch causes xfstests to fail frequently.  The one this trace is
> > from was generic/074.
> 
> Thanks for catching this. The sanity test is not right, so we need to revert
> that one.

Unfortunately, my overnight test run with this patch reverted crashed
again with the same signature.  I also reverted the parent commit,
and when that crashed I also reverted the parent of that.  Which also
crashed.

So maybe there's something else that makes this unstable.  Or maybe my
bisect went wrong.  Or _something_.  Anyway, I'm going to spend much of
today hammering on generic/074 with various kernel versions and see what
I can deduce.

So far I see no evidence that v6.7 crashes with g/074.  And I know that
next-20240125 does crash with g/074.  I'm pretty sure that v6.8-rc1 also
crashes with g/074, but will confirm that.